A: 

I'm not sure how that code you showed will do anything to the browser, or anything special with the F5 key.

I suspect that your problem is a focus issue. I have found that in Firefox (my main browser), if a Flex movie is selected, I cannot use control-T to open a new tab. Yet, if I click into the address bar or some other "non-flex" portion of the page, the new tab opens without any problems. I believe it is because once the Flash Player has focus, the key commands do not get sent to the browser.

I suspect the same issue is happening with IE8. and the F5 / refresh key. I do not have a solution for you.

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